Indian Scientists Warn of H5N1 Bird Flu Pandemic Threat to Humans

Illustration of a bird (Photo: Freepik/Freepik)

JAKARTA - Scientists have long warned of the threat of bird flu (H5N1) that one day could spread widely to humans and trigger a global health crisis.

Avian flu is a type of influenza that is widely found in South Asia and Southeast Asia. This virus first appeared in China in the late 1990s and occasionally infects humans.

World Health Organization (WHO) data recorded from 2003 to August 2025 there were 990 cases of H5N1 in humans in 25 countries, with 475 deaths. Almost half of the sufferers died.

In the United States, more than 180 million poultry were affected. The virus has also spread to more than 1,000 dairy farms in 18 states and about 70 people, mostly farm workers, have been infected. Some have been hospitalized and one person has died.

In India, in January, three tigers and a leopard died from the virus at a wildlife rescue center in Nagpur.

In humans, symptoms of bird flu are similar to severe flu, such as high fever, cough, muscle pain, and sore throat. There are also cases without symptoms. Although the risk of transmission to humans is still low, health authorities continue to monitor H5N1, especially if the virus changes and is easily transmitted between humans.

These concerns prompted two Indian researchers, Philip Cherian and Gautam Menon from Ashoka University to create a model to predict how the H5N1 outbreak could spread to humans and the most effective way to stop it.

The research, published in the journal BMC Public Health, used real data and computer simulations to test various outbreak scenarios.

"The threat of the H5N1 pandemic in humans is real," Prof Gautam Menon told the BBC.

"However, we still have hope to prevent it through better surveillance and rapid and appropriate public health responses," he continued.

Researchers assess that the pandemic likely started from one person who contracted from poultry, such as farmers or market workers. The main danger is not the first case, but the human-to-human transmission afterwards.

They used BharatSim, a simulation platform previously used to model COVID-19. The results showed that the response time was very limited.

When the number of cases reaches two to ten people, the virus almost certainly spreads outside the initial circle. If quarantine is carried out from the first two cases, the outbreak can be stopped. However, if it reaches ten cases, the spread is almost uncontrollable.

Researchers modeled a village in Namakkal district, Tamil Nadu, the center of the poultry industry in India. The village with 9,667 residents is simulated complete with houses, schools, workplaces, and markets.

The virus is introduced through infected poultry, then spreads from the workplace to families and the surrounding environment. Various measures are tested, such as poultry destruction, quarantine, and limited vaccination.

The destruction of poultry is effective if it is carried out before transmission to humans. After that, the speed of response is the key. Isolation of patients and family quarantine can stop the initial spread. However, if the transmission has spread to the third level, the outbreak is difficult to control without extreme measures such as lockdowns.

Limited vaccination helps slow the spread, even if the impact is small within the home. Researchers also found a dilemma that quarantine too early can increase transmission at home, but if it is too late it becomes ineffective.

Researchers acknowledge the limitations of the model, such as only using one village and not yet taking into account changes in human behavior.

"This model assumes very efficient transmission. In fact, not all flu sufferers transmit the virus, and only a small percentage become super spreaders," said Emory University virologist Dr. Seema Lakdawala.

If H5N1 adapts to humans, the impact is expected to be more similar to the 2009 swine flu pandemic than Covid-19. The world is also considered to be more prepared because there are already antiviral drugs and initial stocks of H5 vaccines.

However, Dr. Lakdawala warned that the risk could be greater if H5N1 mixed with other flu viruses, which could potentially change the pattern of seasonal flu in the future.

The researchers stressed that this kind of simulation can be updated in real time and become an important tool for health authorities to make quick decisions at the beginning of an outbreak, before the situation really gets out of control.